by Kirkpatrick, J.G, Step, D.L, Payton, M.E, Richards, J.B, McTague, L.F, Saliki, J.T, Confer, A.W, Cook, B.J, Ingram, S.H, Wright, J.C
Published in Journal of the American Veterinary Medical Association (01.07.2008)

by Tribble L.F, Ingram S.H, Gaskins C.T, Ramsey C.B
Published in Journal of animal science (01.03.1979)